Blame it on chemo brain

Can exercise reduce the forgetfulness caused by anti-cancer drugs?

Scenery Slater went to pick up her mail in the lobby of her West Vancouver apartment building one day, but when she got back into the elevator, she forgot what floor she lived on.

She would try to turn off lamps in her home with a wall switch, only to realize that she had to use the lamp switch.

She would make Yorkshire pudding for herself and her father, determined to halve the recipe, and wind up doubling it instead.

At first, Slater didn’t think any of this had anything to do with her chemotherapy for breast cancer. Then she heard about “chemo brain”—a decline in cognitive function experienced while receiving a powerful cocktail of anti-cancer drugs.

“You don’t hear about chemo brain before starting treatment,” says Slater, 49, who is on leave from her job as an officer with the Canada Border Services Agency. “You get all this information about the drugs you’ll be taking and the possible side effects, and no one mentions that. But when I talk to people who have had chemotherapy, I’ve only come across one who hasn’t experienced some sort of cognitive interruption to some degree or another.”

Now a UBC researcher is trying to determine if there might be a simple remedy—exercise.

Kristin Campbell, an assistant professor in the Department of Physical Therapy, is seeking breast cancer patients for a first-of-its-kind experiment: one group of randomly chosen women engage in a cardiovascular workout four times per week for six months, while another group of women maintain their usual lifestyle.

At the beginning and at the end of their participation, the women take tests of working memory, learning and problem-solving. While they perform simple tasks, they also have their brain function assessed using functional magnetic resonance imaging and electroencephalograms. The study is receiving support from the Canadian Breast Cancer Foundation BC/Yukon chapter.

A growing body of research, some of it by Campbell’s colleague in Physical Therapy, Assistant Professor Teresa Liu-Ambrose, has demonstrated that exercise can improve cognitive function in older adults.

“Exercise and cognition is an emerging field,” Campbell says. “There’s a consensus that there’s something there. But why, and what type of exercise is most important, hasn’t been answered.”

The chemo brain phenomenon gained attention in the 1990s as a result of advocacy by cancer survivors, says Tim Ahles, a behavioural psychologist at Memorial Sloan-Kettering Cancer Center in New York.

“The survivors kept telling us, ‘This is a real problem. It’s not just depression,” Ahles says. “It can affect the ability to return to work or to school, the quality of life, and activities of daily living.”

Some people improve after months or a year, Ahles says. Others never fully regain their cognitive abilities.

Slater, who completed her chemotherapy in the fall of 2010, is still grappling with what she perceives to be diminished mental acuity. Although she doesn’t know how she fared on the tests, she is confronted almost daily by a situation or question that temporarily stumps her. Before cancer and her treatment, she could plow through a novel on a day off; now she has trouble concentrating on anything longer than a paragraph.

But the study led her to discover other benefits of exercise. She is more energetic and sleeping better. Long after her participation ended, she continues to work out on the treadmill in her apartment building, three times a week.